|Rugby World Cup: Australia v Wales|
|Venue: Twickenham Date: Saturday, 10 October Kick-off: 16:45 BST|
|Coverage: Live on BBC Radio Wales, Radio Cymru and BBC Radio 5 live, plus live text commentary on the BBC Sport website.|
Coach Warren Gatland says Wales are "desperate to beat" Australia.
The winners will top World Cup Group A and earn a comparatively easier course to the final than the losers, who will face South Africa in the quarter-final.
Gatland has made six changes to the team that beat Fiji 23-13 last time out for Saturday's encounter at Twickenham.
"You win this group and potentially your road through to quarters, semis and finals is easier than the other side of the draw," he said.
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"We're desperate to finish off well and win this group, and hopefully give ourselves potentially a second seed team in the quarter-finals."
The key changes to the team see Samson Lee and Paul James return to the front row in place of Tomas Francis and Gethin Jenkins, while Justin Tipuric and Sam Warburton team up in the back row.
George North moves to centre from wing, where Liam Williams returns. Gareth Anscombe gets the nod over Matthew Morgan at full-back.
The front row
Of all the Wales changes, the front row selection was perhaps the least surprising.
Despite winning both matches, Wales struggled at the scrum against England and Fiji. Australia's eight had no such problems as they outmuscled England.
"Paul James has had a calf strain so he needed to play. We needed to give him some time," said Gatland.
"Given Gethin Jenkins' history in the past, with three or four games in a row he has broken down so we wanted to make sure we kept him fit and fresh potentially for a quarter-final.
"It's great Samson is back from that injury. He's that typical old-fashioned northern hemisphere tight-head. He's pretty squat and built like the proverbial brick out-house.
"I think with the amount of work we've done there we're confident it will go well."
The back row
Gatland said blind-side specialist Dan Lydiate was being rested to protect a sore eye though "he would have played if it was a final."
His absence sees Wales pairing two specialist open-side flankers in Tipuric and Warburton, with Taulupe Faletau continuing at number eight.
Even without the suspended Michael Hooper, Gatland knows Australia will present a formidable challenge at the breakdown.
"Justin Tipuric deserves an opportunity because he's been absolutely outstanding in the warm-up games," added Gatland.
"It just gives us options. The balance we've had with Sam at open-side and Dan and Taulupe that's outstanding as well.
"It's horses for courses and probably the way the Australians with [David] Pocock - I know Hooper's out - but it's matching them at the breakdown."
Centre and back three
Anscombe was in Gatland's extended squad for the tournament before injuring an ankle in training and missed out on selection.
Injuries to Scott Williams and Hallam Amos opened the door for the former Chiefs player to return, and he gets the nod ahead of James Hook and Morgan, who was full-back against Fiji.
"Matthew Morgan got a knock last week and wasn't able to do full contact until later in the week," said Gatland.
"Gareth has played a lot at full-back- I think two years ago he played the Super Rugby final for the Chiefs at full-back. He's experienced and has the pedigree there.
"It was a chance to put Liam [Williams] back on the wing and a chance to shift George [North] into the centre.
"I like the mix of the backline."
North was at centre when Wales last met Australia in November, and in 2011 said he felt North's long term future was in midfield, not on the wing.
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